The invention relates to building attic ventilation, and more particularly to an improved wooden vent block for positioning between roof rafters at the edge of a pitched-roof attic, and a method of assembling and installing the vent block.
Nearly all building codes require a prescribed minimum area of ventilation openings, depending on the size of the attic space, at the edges of a pitched-roof attic below the eave. Ventilation is required to prevent rot and preserve the wooden structural members.
In the prior art, vent blocks, usually two-by-fours or two-by-sixes, depending on the roof rafter size, had holes with one long patch of insect screen nailed or stapled over the attic side of the holes. Attic insulation was a problem, because it could cover the vent holes. Usually a piece of plywood was angularly toe-nailed between the rafters to hold back the insulation in the area of the vent holes. This was difficult and time-consuming, as well as wasteful of materials. In addition, the attic floor space near the vent blocks was left uninsulated, due to the requirement that the insulation be held back.
Until the present invention described below, no attic vent block arrangement provided a practical, efficient way of solving the problem of providing for attic ventilation in building construction wherein there is to be attic floor insulation.